Synthesis and photochemistry of side-chain liquid crystal polymers based on cinnamate esters

The syntheses of three methacrylate monomers with cinnamate ester side-chains and of a further monomer with a corresponding cinnamide side-chain are described. Two of the monomers, with isomeric structures, were thermotropic liquid crystals. Although the clearing points were very similar the crystal melting points differed by 8°C. One compound also exhibited a monotropic smectic phase, behavior not shown by its isomer. The other two monomers were not liquid crystalline. The monomers were polymerized by free radical polymerization, both as homopolymers and as copolymers with methyl methacrylate. In the case of one of the mesogenic ester monomers, copolymers with a cyanophenyl benzoate monomer were also prepared. Three of the four monomers formed thermotropic liquid crystalline homopolymers and the copolymers with the benzoate monomer were also liquid crystalline. The monomers were considered as photoactive components of polymeric liquid crystals. As a preliminary investigation of their photochemistry, copolymers with methyl methacrylate were prepared and irradiated in solution with a broad-band source. Under these conditions two of the materials show a facile photo-Fries rearrangement of the aryl cinnamate ester group. © 1992 John Wiley & Sons, Inc.     

Effects of cobalt-60 γ-ray irradiation on fresh-keeping and storage of kiwifruits

The boxes contained kiwifruits were irradiated with cobalt-60 γ-rays at different dosages (0.6 , 1.8 and 3.6 KGy) and stored in a room ventilated at night, the natural ambient air being used as cool source.The results showed that the treatment which fruits irradiated with 0.6 KGy was the best after 85 days. It gave the normal-fruit rate of 95.10%, fruit flesh hardness of 4.10 Kg · cm^-2, fresh and plump fruits, good quality and less Vc loss.     

原油溶胶-凝胶等温转变过程中的流变性研究

使用RS75流变仪，采用小振幅振荡剪切方法和稳态剪切方法对含蜡原油在溶胶 -凝胶等温转变过程中的流行了研究．结果表明，等温转变成的凝胶原油的结构在 很大程度上决定于预剪切速率，非牛顿含蜡原油在结构恢复过程中表现出不可逆的 触变特性．而凝胶原油在外力作用下向溶胶状态转变的过程中，要经历从线性粘弹 性变形，到非线性粘弹性变形，再到结构屈服的过程，且高剪切应力下的溶胶原油 结构与预剪切速率无关．     

Preparation and mechanical properties of thermal energy storage microcapsules

A series of heat energy storage microcapsules was prepared using melamine-formaldehyde resin as the shell material and the mechanical properties of the shell were investigated. A phase change material whose melting point was 24 °C was used as core and the quantity of heat involved in phase transition was 225.5 J/g. Average diameter of the microcapsules varied from 5 to 10 μm, and the globular surface was smooth and compact. The mechanical properties of the shell were evaluated by observing the surface morphological structure change after application of pressure by means of scanning electron microscopy. When the mass ratio of the core and shell material is 3:1, a yield point of about 1.1×10⁵ Pa was found and when the compression was increased beyond this point the microcapsules showed plastic behavior. This has been attributed to the cross-link density and to the high degree of reaction of the shell material. Different yield points subsequently reflected differences in the mechanical behavior. It was also found that the mechanical intensity of double-shell microcapsules was better than that of single shelled ones.     

油溶性偶氮染料的合成及其性能研究

随着染料在现代科技中的广泛应用,染料的油溶性也日益受到人们的重视.如:非线性光学材料、激光盘光学信息存贮材料中使用的染料、彩色成像中的油溶性影像染料等,对染料在有机溶剂中的溶解度都有很高的要求.偶氮染料是有机染料中的主要类型,但目前对其分子结构与油溶性关系的研究甚少.本文合成了一类黄色偶氮染料(见表1),并对其色光、油溶性等性能进行了测试,发现取代基相对于偶氮基的位置,是影响偶氮染料油溶性的主要因素.     

Silica-supported Copper（Ⅱ） Catalyzed Coupling of Arylboronic Acids with Imidazoles

Immobilized copper（Ⅱ） in organic-inorganic hybrid materials catalyzed Ar-N coupling of arylboronic acids with imidazoles has been developed. Arylboronic acids reacted with imidazoles smoothly in the presence of a 3-（2-aminoethylamino）propyl functionalized silica gel immobilized copper（Ⅱ） catalyst （10 mol%） in methanol without any additives and bases. The reactions generated the corresponding cross-coupling products in good yields. Furthermore, silica-supported copper can be recovered and recycled by a simple filtration procedure and used for five consecutive trials without decreases in activity.     

基于国际化产科教融合实训平台的教学模式改革与实践

在分析当前省属工科院校教育以能力为导向培养目标完成实施过程中遇到国际化困难问题的基础上，以青岛大学材料学科为例，提出了基于国际化产科教融合实训平台的教学模式改革举措，并经过实践验证证实其切实可行。包括：充分整合校内外材料学科整体资源，建立了国际化的产科教深度融合实训平台，构建了高效的国际化产科教深度融合协同育人实训平台动态管理运行机制；以实训平台为依托实现师资队伍、教学内容、教学模式、科研等全方位的国际化改革；基于国际化产教研融合实训平台的教学模式改革的实践收到显著成效，对全国省属高等院校理工学科专业建设国际化改革的推广有较好的示范作用。     

Formation of SnO2 Nanoparticles on External Surface of NaY Zeolite

Tin dioxide nanoparticles of 5 nm in size were prepared on NaY zeolite external surface by impregnation of SnCl2 solution and subsequent calcination at 623 K. A SnO2-NaY based chemical sensor for detecting H2 was demonstrated.     

Oxygen diffusion in SrCe<Subscript>0.95</Subscript>Yb<Subscript>0.05</Subscript>O<Subscript>3−δ</Subscript>

¹⁸O/¹⁶O isotope exchange depth profiling (IEDP) combined with secondary ion mass spectrometry (SIMS) has been used to measure the oxygen tracer diffusivity of SrCe_0.95Yb_0.05O_3– between 800 °C and 500 °C at a nominal pressure of 200 mbar. The values of D* (oxygen tracer diffusion coefficient) and k (surface exchange coefficient) increase steadily with increasing temperature, and the activation energies are 1.13 eV and 0.96 eV, respectively. Oxygen ion conductivities have been calculated using the Nernst–Einstein equation. The transport number for oxide ions at 769 °C, the highest temperature studied, is only ~0.05. Moreover, SrCe_0.95Yb_0.05O_3– has been studied using impedance spectroscopy under dry O₂, wet O₂ and wet H₂ (N₂/10% H₂) atmospheres, over the range 850–300 °C. Above ~550 °C, SrCe_0.95Yb_0.05O_3– shows higher conductivity in dry O₂ than in wet O₂ or wet H₂; below that temperature the results obtained for the three atmospheres are comparable. Dry O₂ shows the highest activation energy (0.77 eV); the activation energies for wet O₂ and wet H₂ are identical (0.62 eV).Abbreviations HTPC high-temperature proton conductor - IEDP isotope exchange depth profiling - SIMS secondary ion mass spectrometryPresented at the OSSEP Workshop Ionic and Mixed Conductors: Methods and Processes, Aveiro, Portugal, 10–12 April 2003     

Fluorine-doped nanocrystalline SnO2 powders prepared via a single molecular precursor method as anode materials for Li-ion batteries

Fluorine-doped nanocrystalline tin dioxide materials (F:SnO₂) have been successfully prepared by the sol-gel process from a single molecular precursor followed by a thermal treatment at 450-650 °C. The resulting materials were characterized by FTIR spectroscopy, powder X-ray diffraction, nitrogen adsorption porosimetry (BET) and transmission electron microscopy (TEM). The mean particle size increased from 5 to 20 nm and the specific surface area decreased from 123 to 37 m²/g as the temperature of heat treatment was risen from 450 to 650 °C. Fluorine-doped nanocrystalline SnO₂ exhibited capacity of 560, 502, and 702 mA h/g with 48%, 50%, and 40% capacity retention after 25 cycles between 1.2 V and 50 mV at the rate of 25 mA/g, respectively. In comparison, commercial SnO₂ showed an initial capacity of 388 mA h/g, with only 23% capacity retention after 25 cycles.